Plug-in hybrid will redefine what's expected from a 'green car'

By Graeme Fletcher, Postmedia News

Originally published: August 7, 2013

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MIRAMAS, FRANCE — The fundamental thrust of the BMW i8 is to reduce the consumption of energy without detracting from the fun of the drive. It really is that simple. Well, almost. The question that remained after driving the i8 at BMW’s secretive Autodrome de Miramas proving ground is whether the automotive world is ready for a car that will reshape the landscape and redefine what’s expected of the next-generation green car.

The i8 certainly has performance galore and, in spite of its ugly blue/white camouflage, some seriously seductive curves to go along with the sweeping profile demanded of a supercar. On the flip side, it boasts an astounding European average fuel economy of 2.5 litres per 100 kilometres. Even when pushed around the track, the average consumption remained below 10 L/100 km. Try that in a Porsche 911.

Accessing the i8’s four seats — it’s a 2+2 with comfortable front seats and token rear pews — is through a sexy set of scissor-style doors. With both in the open position the i8 looks as though it is ready to star in the next Batman movie. It also boasts an enviable 0.26 co-efficient of drag — just about every panel is used aerodynamically, including the flat undertray and aero-style wheels. It just goes to show that a sexy form can be just as functional.

As with the i3, the i8 uses a blend of aluminum and carbon-fibre-reinforced plastic (CFRP) to help to offset the battery’s 98-kilogram weight — the i8’s curb weight is just 1,490 kilograms, 200 kg lighter than the M3.

At the heart of the i8 plug-in hybrid is an all-new 1.5-litre, turbocharged 3-cylinder gasoline engine with an air-to-water intercooler. It produces 231 horsepower and, more importantly, 236 pound-feet of torque. It drives the rear wheels through a six-speed automatic transmission with Normal and Sport modes. The other half of the hybrid is an electric motor that chips in with 131 hp and 184 lb-ft of torque. It drives the front wheels through a two-speed automatic transmission (one gear for electric-only driving, the other for the rest of the time). It gets its power from a lithium-ion battery, which is mid-mounted in what would be the central tunnel. Of the battery’s 7.2 kilowatt/hour capacity only 5 kW/h is utilized, which extends the battery’s life.

As with BMW’s regular cars, the i8 features Driving Experience Control. It allows the driver to pick the right mode for the circumstance. Comfort balances performance with efficiency, while Sport turns the up wick up and produced a way bigger smile. At the touch of a button the driver can also engage Eco Pro — it softens everything and alters the heater/air conditioning operation to extract the best economy and efficiency.

And so to the all-important numbers: The i8 has a combined output of 362 hp, which is very good. However, it pales in comparison to the 420 lb-ft of torque the i8 makes at impossibly low speeds. Obviously, the equates to scintillating performance — the i8 scampers to 100 kilometres an hour in 4.5 seconds, accomplishes the more important 80-to-120-km/h passing move in 4.5 seconds and blasts forth to its electronically limited top speed of 250 km/h without missing a beat.

The reality is the i8 feels so much faster because of the abundant torque and the fact it turns up the instant the i8 begins to move. From there on, it just piles on the speed in a completely seamless manner — between 10 and 168 km/h (my top track speed) the i8 never let up. To put the turn of speed into perspective, it felt every bit as fast and furious as the M3.

It also sounds the part — only under light throttle does the exhaust tone have a hint of the tinny sound for which three-bangers are known. At full chat, the i8’s sound is rewardingly sporty and just as soul-stirring.

After the main battery has been fully recharged, which takes less than two hours with the wall box charger (four hours using 110-volts), selecting the electric drive mode delivers a range of 35-km and a top electric-only speed of 120 km/h. The better news is the overall driving range — in Comfort mode the i8 has a range of 500 km. Engaging Eco Pro can improve this number by up to 20%.

Regenerative braking plays a key role. The amount of regen braking is influenced by the drive mode selected — in Sport it is more aggressive and it uses the engine’s 10-kilowatt high-capacity starter motor as a generator to supplement the main electric motor’s regenerative efforts. In an unusual twist, it also uses the starter/generator like an electric supercharger to spin the engine up to the right revs so it matches the electric motor when the two are working together. This eases the transition between electric and gas/electric modes.

The unspoken advantage to the i8’s layout is the on-demand all-wheel-drive ability the engine and motor deliver. This not only keeps unwanted wheelspin at bay, it adds a great deal to the i8’s road manners. For example, when heading into a corner, it sends more power rearward, which reduces understeer, and then transfers more of the drive forward to pull the i8 out of the corner. Of course, the fact the chassis is balanced, featuring a perfect 50/50 weight distribution front-to-rear, helps matters enormously. In the end, my track session proved the i8 to be deliciously neutral — there was minimal understeer and it would flick its tail out when provoked.

When it comes to the ride side, the i8 is as sweet and integrated as the powertrain. The driver-adjustable suspension (Comfort and Sport) along with the optional tires combined to deliver a drive that saw the amount of body roll limited to a degree or two, yet the ride remained remarkably refined — the Miramas track is glass-smooth, so that has to be factored in, but the i8 did ride more like a full-on luxury car than a hybrid supercar. The steering was also nicely weighted and the brake pedal was devoid of the mushiness that defines most hybrid brake systems.

The test session at Miramas did prove one thing — the i8 needs its optional tire package. The base, low-rolling resistance tires measure P195/50R20 up front and P215/45R20 at the back. The optional rubber replaces them with P215/45R20 and P245/40R20 respectively. They deliver much better lateral grip and sharpen the handling appreciably.

The i8 is slated for launch in 2014. BMW has not announced the price yet, but unofficially said it will be between $139,000 and $208,000 (figures converted from Euros to Canadian dollars). I figure somewhere around $175,000 sounds about right. The world debut of the production i8 will take place at the 65th International Motor Show in Frankfurt in September.